Chemical composition of some tissues of the Antarctic fish Notothenia rossii marmorata,fischer 1885

Muscle, liver, stomach, intestinal tract and pyloric caeca of the Antarctic fish Notothenia rossii marmorata, Fischer 1885, were analysed for dry matter, crude protein, carbohydrate, total lipids, ash, chloride, phosphorus and fluoride. It was found that the levels of these classes of substance varied considerably within ten fishes of a pre-spawning community.The highest level of protein was found in the stomach (80·8% mean value on a dry weight basis) and the lowest in the liver (39·6%); for total lipids in the liver and stomach the situation was reversed with the relevant figures being 40·8% and 11·27%, respectively. The pyloric caeca showed a maximum of ash content (6·34%), whilst only 3·92% was found in the liver. The liver was extremely rich in carbohydrates (8·22%) whilst, at 1·64%, the muscle contained least. Although N. rossii marmorata mainly feeds on the fluoride-containing krill (Euphausia superba Dana), the tissues investigated showed only a low level of fluoride (10–40 ppm).     

Occurrence of histamine in canned tuna fish from Iran

Histamine fish poisoning is a significant public health and safety concern and also a trade issue. Histamine was investigated in canned tuna fish in Qazvin province from Iran by ELISA method. Histamine was detected in 29.37 % canned tuna fish samples. The overall mean level of histamine was 8.59 ± 14.24 ppm and the concentration was between 2.51 and 74.56 ppm. Except four samples (2.50 %) of 47 positive canned tuna fish samples, histamine content of other positive samples was in compliance with Food and Drug Administration (FDA) legislation (lower than 50 ppm). Most canned tuna fish contain histamine with high mean value was produced in summer (52.50 %) and spring (47.50 %) seasons, the mean levels of histamine were 6.30 and 12.62 ppm in these positive samples, respectively. The results of this study indicate that the most canned tuna fish produced in Qazvin province of Iran has histamine levels lower than the allowable limit suggested by FDA. Further studies should be carried out to investigate the presence of this toxin and other biogenic amines in different fish and sea food products.     

Proximate composition and selected mineral content of commercially important fish species from the black sea

Proximate composition, selected mineral (Zn, Fe, Cd, As, Hg, Pb, Ni, Cu) content and fatty acid profiles were determined in some widely consumed fish species obtained from the Black Sea. All fish species analysed individually were fairly high in protein (14·1–25·1%) and lipid (7·4–18·4%). Moisture and ash content varied within a narrow range. The mineral content was highly variable. The most abundant microelements in fish were Zn and Fe followed by Cu, and the remaining elements were present in amounts below toxic levels. Eight fatty acids (16: 0, 16:1, n-7, 18: 0, 18:1 n-9, 18: 2 n-6, 20:1 n-9, 20: 5 n-3, 22: 6 n-3) represented more than 60% of the fatty acid content. Saturated fatty acids ranged from 25·8 to 45·1%. Anchovy and whiting contained almost 35% of polyunsaturated fatty acids. The percentage of docosahexaenoic acid (DHA) exceeded that of eicosapentaenoic acid (EPA) in almost all the fish species examined, and the actual content of these acids has shown that sprat, whiting, garfish, red mullet, shad and sea bream provide the recommended daily intake of 1 g of EPA+DHA with reasonable amounts of fillet. These results indicate that biological differences existing in fish species can influence the values to be set for the standards and composition. © 1998 Society of Chemical Industry.     

PRODUCTION OF DIACETYL, 2-ACETOLACTATE AND ACETOIN BY YEASTS DURING FERMENTATION

Results are given for the production of diacetyl, 2,3-pentandione- I-acetolactate, 2-acetohydroxy butyrate, acetoin and 3-hydroxy-2-pentanone for 13 yeasts belonging to the genus Saccharomyces. The data presented indicate that in general the yeasts do not produce significant amounts of vicinal diketones during unstirred laboratory fermentations. The observed maximum levels of diacetyl ranged from 0·02–0·32 ppm averaging 0·09 ppm (0·07 ppm if S. carlsbergensis (strain H) is omitted). During active fermentation all the yeasts tested produced 2-acetohydroxy acids. The 2-acetohydroxy acids and the 3-hydroxy-2-ketones are determined gas chromatographically by stepwise conversion of the four compounds to diacetyl and 2,3-pentandione. The maximum amounts of 2-acetolactate produced by the yeasts tested averaged 0·7 ppm, ranging from 0·08–1·65 ppm.     

Degradation of sorbic acid in fruit squashes and fish paste

Degradation of sorbic acid (SA) in fruit squashes and fish paste has been found to be influenced by the nature of the food material and the packaging system. Losses in SA ranged from 60–90% in polypropylene and 41–65% in saran coated cellopoly pouches to 22–30% in paper-aluminium foil-polyethylene laminate pouches and glass bottles after 150–210 days at 37°C. The rate of degradation was significantly higher in fish paste than in fruit squashes.
The major portion of the added SO, in fruit squashes was lost during the initial stages of storage and the residual SO, (< 100 ppm) did not significantly influence the rate of degradation of SA. Browning intensity in fruit squashes and fish paste was also related to the oxygen permeability of the packaging materials. Addition of 0.1 % SA did not significantly influence the rate of browning but at 0.2%, a slight increase in the rate was observed.     

Malonaldehyde content of indigenous and imported foods and foodstuffs in Nigeria

Several types of imported and locally available foods and foodstuffs in Nigeria were analysed for their malonaldehyde concentrations. The malonaldehyde levels of imported canned fish products ranged from 0·32 to 3·32 mg/kg. Thermal treatment of mackerel (Scomber scombus) reduced its malonaldehyde level but increased the oncogenic substance of other fish samples. Freezing beef for 4 days increased the malonaldehyde level with a mean of 0·48 mg/kg. The extract from boiled liver had a higher malonaldehyde level than that from raw liver. Milk and milk products did not contain any detectable quantity of malonaldehyde. The need to determine the cumulative effect(s) of ingesting small quantities of malonaldehyde for long periods and further appraisal of all food items for this oncogene are discussed.     

Listeria monocytogenes contamination patterns for the smoked fish processing environment and for raw fish

Reliable data on the sources of Listeria monocytogenes contamination in cold-smoked fish processing are crucial in designing effective intervention strategies. Environmental samples (n = 512) and raw fish samples (n = 315) from two smoked fish processing facilities were screened for L. monocytogenes, and all isolates were subtyped by automated ribotyping to examine the relationship between L. monocytogenes contamination from raw materials and that from environmental sites. Samples were collected over two 8-week periods in early spring and summer. The five types of raw fish tested included lake whitefish, sablefish, farm-raised Norwegian salmon, farm-raised Chilean salmon, and feral (wild-caught) salmon from the U.S. West Coast. One hundred fifteen environmental samples and 46 raw fish samples tested positive for L. monocytogenes. Prevalence values for environmental samples varied significantly (P < 0.0001) between the two plants; plant A had a prevalence value of 43.8% (112 of 256 samples), and plant B had a value of 1.2% (3 of 256 samples). For plant A, 62.5% of drain samples tested positive for L. monocytogenes, compared with 32.3% of samples collected from other environmental sites and 3.1% of samples collected from food contact surfaces. Ribotyping identified 11 subtypes present in the plant environments. Multiple subtypes, including four subtypes not found on any raw fish, were found to persist in plant A throughout the study. Contamination prevalence values for raw fish varied from 3.6% (sablefish) to 29.5% (U.S. West Coast salmon), with an average overall prevalence of 14.6%. Sixteen separate L. monocytogenes subtypes were present on raw fish, including nine that were not found in the plant environment. Our results indicate a disparity between the subtypes found on raw fish and those found in the processing environment. We thus conclude that environmental contamination is largely separate from that of incoming raw materials and includes strains persisting, possibly for years, within the plant. Operational and sanitation procedures appear to have a significant impact on environmental contamination, with both plants having similar prevalence values for raw materials but disparate contamination prevalence values for the environmental sites. We also conclude that regular L. monocyrogenes testing of drains, combined with molecular subtyping of the isolates obtained, allows for efficient monitoring of persistent L. monocytogenes contamination in a processing plant.     

Contamination levels of PCDDs, PCDFs and CoPCbs in fish oils used as raw materials for margarine and shortening and retailed fish

Toxic equivalent (TEQ) levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) and coplanar polychlorinated biphenyls (CoPCBs) were analyzed in both crude (n = 5) and refined-hardening fish oils (n = 2), which are used in part as the raw materials of margarine and shortening, and in some retailed fish (n = 6), which may be similar to those used as sources of fish oil. PCDDs/DFs-TEQ levels ranged from 0.1 to 13.5 pg TEQ/g fat weight in crude fish oils, from 0.5 to 1.6 pg TEQ/g fat weight in refined-hardening fish oils, and ranged from 1.4 to 31.2 pg TEQ/g fat weight in retailed fish. The ranges of PCDDs/DFs-TEQ in crude fish oils, in refined-hardening fish oils and in retailed fish overlapped each other. In addition, CoPCBs-TEQ levels ranged from 4.9 to 19.6 pg TEQ/g fat weight in crude fish oils, from 0.2 to 1.4 pg TEQ/g fat weight in refined-hardening fish oils, and from 2.7 to 165.8 pg TEQ/g fat weight in retailed fish. TEQ levels of CoPCBs in refined-hardening fish oils were much lower than those in crude fish oils and in retailed fish. This was due to the lower concentrations of less-chlorinated congeners in refined-hardening fish oils, as compared to those in crude fish oils and retailed fish. It appears that less-chlorinated PCBs congeners in refined-hardening fish oils are partly removed during the refining process.     

Histamine contents of fermented fish products in Taiwan and isolation of histamine-forming bacteria

Twenty-seven imported fermented fish products from Southeast Asian countries and sold in the supermarkets in Taiwan, including fish sauce, fish paste and shrimp paste, were tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, salt content, total volatile basic nitrogen, trimethylamine, and aerobic plate count in all samples ranged from 4.8% to 6.5%, 16.2% to 45.3%, 51 to 275 mg/100 g, 5.4 to 53.9 mg/100 g and 1.0 to 4.2 log CFU/g, respectively. The average content for each of eight different biogenic amines in all samples was less than 90 ppm, except for histamine which has an average content of 394 ppm in fish sauce, 263 ppm in fish paste, and 382 ppm in shrimp paste. Most of the tested fermented fish products (92.6%) had histamine levels greater than the FDA guideline of 50 ppm, while seven of them (25.9%) contained >500 ppm of histamine. Although Bacillus coagulans and Bacillus megaterium were identified as the two histamine-producing bacteria capable of producing 13.7 and 8.1 ppm of histamine, respectively, in trypticase soy broth broth supplemented with 1.0% l-histidine, they were not determined to be the main contributors to histamine accumulation in these fermented fish products.     

THE INFLUENCE OF 2-ACETOHYDROXY ACIDS ON THE DETERMINATION OF VICINAL DIKETONES IN BEER AND DURING FERMENTATION

During sampling and determination of diacetyl, 2-acetohydroxy acids are easily converted to vicinal diketones. A simple procedure for gas chromatographic determination of diacetyl, 2-acetolactate, acetoin and the homologous compounds is given. By careful sampling, less than 0·01 ppm of diacetyl was detected during the main fermentation in one brewery, whereas another strain of brewer's yeast yielded a maximum of 1·7 ppm of diacetyl. When samples of fermenting liquids are exposed to air at 60°C, complete conversion of 2-acetohydroxy acids takes place in less than one hour. The possibility that part of 2-acetolactate may be converted to acetoin, however, cannot be excluded. In finished beer 2-acetolactate levels of 0·2–0·5 ppm were observed. During the main fermentation the values ranged from 0·5–2·5 ppm.     

ε-(γ-Glutamyl)lysine Crosslink Distribution in Foods as Determined by Improved Method

Quantitative analysis of ε-(γ-glutamyl)lysine crosslink in 127 foods was achieved with a, preliminary separation by reverse phase-HPLC before o-phthalaldehyde derivatization to remove interfering peaks. ε-(γ-Glutamyl)lysine was detected in 96 foods and its contents ranged from 0.2 to 135 μmol/lOOg protein. High levels were found in fish paste products, processed fish, shellfish, meats and soybeans, and raw poultry organs. For fish and meats, the level of ε-(γ-glutamyl)lysine in processed foods and fish paste was relatively higher than that in raw materials. The improved procedure could be applied for screening materials with transglutaminase activities.     

A comparative study of quality and safety of Atlantic cod (Gadus morhua) fillets during cold storage,as affected by different thawing methods of pre‐rigor frozen headed and gutted fish

BACKGROUND

The catch of marine whitefish is typically seasonal, whereas the land‐based processing industry has a need for all‐year stable supply of raw materials. This challenge can be met by applying fish frozen at sea. When using frozen fish, the methods employed for thawing may influence the safety and quality of the final product. This study aimed to investigate the applicability of novel thawing strategies in order to provide an all‐year supply of high‐quality and safe cod products.

RESULTS

Comparative investigations of quality and safety factors after thawing in water, with and without air circulation, and contact thawing were performed. The parameters included water‐holding capacity, thawing loss, drip loss, cooking yield, sensory evaluation and microbiological analyses (including total volatile bases nitrogen). Water thawing with air circulation provided faster thawing than water thawing without air circulation and contact thawing. For all three methods, the quality of the thawed fish was acceptable and the shelf life of the fillets during chilled storage was between 10 and 14 days post‐filleting.

CONCLUSION

The results show that controlled freezing of cod, followed by appropriate thawing, may provide the processing industry with an all‐year delivery of raw materials, without compromising quality and safety of the final product. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Lipid and flavour quality of stored breast meat from broilers fed marine algae

In the current study, broilers were fed either 2·8 or 5·5% natural golden marine algae (MA) or 2·1% menhaden oil in an effort to produce an n-3 fatty acid (FA) enriched broiler breast product with acceptable flavour and lipid quality. Previously cooked or raw breast samples were stored at -23°C for 82 d and evaluated at intervals for flavour and TBA values. All treatments significantly increased breast n-3 FA content compared to samples from control-fed birds. The greatest n-3 FA deposition (212 mg kg⁻¹) was achieved by feeding 5·5% MA. All dietary n-3 FA significantly reduced flavour scores compared to samples from control-fed birds, although 2·8% MA samples were still considered acceptable by consumer panelists. Deterioration of flavour quality during storage of previously cooked samples was accelerated by all n-3 FA treatments except 2·8% MA. The rate of TBA production during storage of cooked breast meat was increased by n-3 FA, but this was curtailed by storing samples raw. These data indicate that 2·8% MA is useful for enhancing poultry tissue n-3 FA with minimal compromise in flavour or lipid quality, thus yielding a product that may serve as a substitute for fish in the diet. © 1988 Society of Chemical Industry     

Influence of mercury bioaccessibility on exposure assessment associated with consumption of cooked predatory fish in Spain

BACKGROUND: Predatory fish tend to accumulate high levels of mercury (Hg). Food safety assessment of these fish has been carried out on the raw product. However, the evaluation of the risk from Hg concentrations in raw fish might be modified if cooking and bioaccessibility (the contaminant fraction that solubilises from its matrix during gastrointestinal digestion and becomes available for intestinal absorption) were taken into account. Data on Hg bioaccessibility in raw predatory fish sold in Spain are scarce and no research on Hg bioaccessibility in cooked fish is available. The aim of the present study was to evaluate Hg bioaccessibility in various kinds of cooked predatory fish sold in Spain to estimate their health risk. RESULTS: Both Hg and bioaccessible Hg concentrations were analysed in raw and cooked fish (swordfish, tope shark, bonito and tuna). There were no changes in Hg concentrations during cooking. However, Hg bioaccessibility decreased significantly after cooking (42 ± 26% in raw fish and 26 ± 16% in cooked fish), thus reducing in swordfish and tope shark the Hg concentration to which the human organism would be exposed. CONCLUSION: In future, cooking and bioaccessibility should be considered in risk assessment of Hg concentrations in predatory fish. Copyright © 2011 Society of Chemical Industry     

Storage, Functional and Processing Characteristics of Pre- and Postrigor Beef Preblends for Wiener Production

Pre- and postrigor coarse ground beef was preblended with either salt, salt plus antioxidants or salt plus nitrite and stored for an extended period of time at 2°C. Although prerigor preblends had a lower pH and more salt-extractable protein, smokehouse yields for pre- and postrigor wiener batters were similar. Wieners prepared from prerigor raw materials were generally more acceptable in appearance, flavor and juiciness and more desirable than wieners prepared from postrigor raw materials. Desirable sausage making qualities of prerigor beef raw material can be maintained by pre-blending raw material with 3% salt plus 60 ppm nitrite, packaging preblends to minimize exposure to air and storing at 2°C for up to 28 days. Addition of a mixture of butylated hydroxyanisole, butylated hydroxytoluene and citric acid to the preblend had no effect on functional quality of the raw materials.     

Effects of retort conditions on ATP-related compounds in pouched fish muscle

To examine the usefulness of high-temperature short time (HTST) process on quality of retorted fish products, adenosine triphosphate (ATP)-related compounds in raw fishes and retorted fish models (10 g/pouch) heated at 115 °C for 90 min (common retort (CR) process) or 125 °C for 9 min (HTST process) were analyzed by HPLC method. The raw materials used in this study were fresh chub mackerel Scomber japonicus for sashimi (raw eating), frozen-thawed yellowfin tuna Thunnus albacares for sashimi, frozen-thawed pink salmon Oncorhynchus gorbuscha for cooking and frozen-thawed pink shrimp Pandalus borealis for sashimi. In all the fish samples, the level of inosine monophosphate (IMP), an umami-taste compound, was higher in HTST fishes than in CR fishes. On the other hand, inosine (HxR) and hypoxanthine (Hx), no-taste and bitter taste compounds, was high in CR fishes. K-value, an index of fish freshness defined as the ratio of the sum of HxR and Hx to the sum of ATP-related compounds, was high in CR fishes. In sensory test of pink salmon by the paired difference test, umami and sweetness in the HTST fish were stronger than the ones of the CR fish. The bitterness was stronger in the CR fish rather than in the HTST fish. These results indicated that HTST is a favorable process for retorted fish product and measurement of ATP-related compounds is useful for the quality check of retorted fishes.     

Effect of Delayed Processing on Changes in Histamine and Other Quality Characteristics of 3 Commercially Canned Fishes

ABSTRACT: Changes in histamine and other quality characteristics were examined in 3 commercially important fishes, tuna ( Katsuwonus pelamis ), seerfish ( Scomberomorus commersonii ), and sardines ( Sardinella gibbosa ) through the canning process, at 3 different stages (raw, precooked, and canned) immediately on receipt and also after a delay of 6 h at ambient temperature (30 ± 2 °C). Tuna and seerfish remained sensorially acceptable when processed after delay, whereas sardines exhibited slight ammoniacal/putrid odor. TMA-N and TVB-N contents were low in precooked fish compared with their fresh counterparts, whereas in canned fish, both compounds increased significantly ( P < 0.05). Histamine content in the fish held for 6 h increased to 14, 17, and 8 ppm in tuna, seerfish and sardine, respectively, and never exceeded the maximum permissible limit of 50 ppm prescribed by the U.S. Food and Drug Administration. In precooked and canned fish, histamine was lower than in their raw counterparts and found to be within the range of 1.6 to 8.0 ppm in precooked and 1.2 to 4.3 ppm in canned fish. Holding the fishes destined for canning at 30 ± 2 °C for 6 h, therefore, was found to be safe from histamine toxicity problems.     

Content of strontium,lithium and calcium in selected milk products and in some marine smoked fish

The strontium, lithium and calcium contents have been determined in 87 samples of five kinds of milk‐fermented products, as well as in 93 samples of ten kinds of marine smoked fish. The samples were purchased on the local market. The representative samples were dry ashed in quartz crucibles and the ash was treated with suitable amounts of conc. HCl and a few drops of conc. HNO₃. The obtained sample solution was then used for the determination of Sr, Li and Ca by the flame atomic absorption spectrometry (AAS) method. Ca and Li were determined using the air‐acetylene flame and Sr with nitrous oxide‐acetylene flame, according to the manufacturer's recommendations. The contents of Sr in the fermented milk products ranged from 0.21 to 0.79 (mean 0.44 ± 0.07) and in the marine smoked fish from 0.02 to 4.63 (mean 1.16 ± 0.24) mg/kg of the edible form of both products. Li contents in the milk products ranged from 0.01 to 0.50 (mean 0.07 ± 0.04) and in the smoked fish from 0.00 to 0.58 (mean 0.11 ± 0.08) mg/kg. The calcium was highest in the milk products and ranged from 1 010 to 2 020.0 (mean 1 377 ± 143) mg/kg. In the smoked fish calcium varied strongly and ranged from 40 to 1 052 (mean 303 ± 53) mg/kg of the edible form. The calculated average ratio of strontium to calcium (mg Sr/1 g Ca) in the milk beverages and yogurts amounted 0.32 and in the smoked fish was 12 times as high and amounted 3.84. The main purpose of this work was to present Ca, Sr and Li together. This is justified because Sr and to some extent also Li are able to modulate Ca metabolism and vice versa.     

大豆蛋白和鱼肉复合挤压过程中水分状态变化研究

大豆蛋白含有丰富的氨基酸,同时鱼肉的脂肪比较丰富,鱼糜相关制品在我国的开发存在很大的发展空间。以大豆蛋白和鱼糜为原料,采用双螺杆挤压机对其进行复合挤压组织化,研制出一种新型的复合蛋白产品。利用低场核磁共振分析测得不同加工工艺条件下的复合蛋白产品自由水与结合水的相对变化情况,并对其变化规律进行分析。同时,对产品和原料的常规理化指标进行了检测与比较。结果表明:新型复合蛋白产品的保水性较好,自由水与结合水含量相对合理,蛋白质含量与脂肪含量等理化指标符合健康食品的标准。     

食品级海洋鱼油的品质分析与控制

分析了国际上对食品级鱼油的卫生、理化指标的相关标准,归纳了相关企业先进的鱼油生产工艺,并检测了实验室自制和市场上的鱼油产品的品质指标.结果表明,选择安全、低污染的原料,通过先进的精炼工艺,采用合理的保护措施,得到的成品鱼油,可满足欧共体法规和国际EPA和DHA组织标准,达到食用、保健级海洋鱼油要求.